Aluminum nitride ceramic bodies have recently received considerable attention, particularly as substrates for integrated circuit packages Such bodies have a high electrical resistivity (at least 10.sup.11 ohm cm), a dielectric constant on the order of 8-10 and a low coefficient of thermal expansion that closely matches silicon. Of particular interest, however, is the potentially high thermal conductivity of an aluminum nitride body. This characteristic permits ready dissipation of heat, generated either during fabrication of an integrated circuit or during subsequent operation, thereby avoiding thermal degrading of electrical properties.
Theoretically, fully densified, pure aluminum nitride has a thermal conductivity of about 320 W/m.sup.o K. However, actual values in the range of 30-60 W/m.sup.o K were obtained with either sintered or hot pressed bodies of undoped aluminum nitride.